clarify that `changelog-seen = 1` goes to the beginning of config.toml
clarify that `changelog-seen = 1` goes to the beginning of config.toml

Fixes #77105

graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust